Unblocking a bathroom gully

[DeckChair-Dave]

The "outside" gully for my Bath/Shower & Bathroom Wash Basin is actually inside the garage that has been built onto the side of the house.

The gully overflowed recently when I emptied a full bath of water. When I investigated I found that the gully was almost totally blocked with a build-up of grey/white material. This stuff is either a build-up of soap deposits, or possibly tile-grout that someone (not me) has poured down the drain in the past.
I've been able to chip away most of it with a screwdriver, (it's not rock hard, soft enough to chip away - just difficult to get at).

Two questions –
1: Should I suspect foul play – or could this be just a build-up of deposits.
2: Is there anything I can buy to pour down the gully that will either dissolve the stuff or at least soften it up.

If it’s relevant, the house is 40 years old and over the last 20 years there have been many extended periods when the house has only been used at weekends.

 

[Agile]

Probably only lime deposits from the soap.

Easier to chip every 6 months but you could use strong HCl if you know how to use it.

Tony

 

[DeckChair-Dave]

Tony – Thanks for your comments – I reckon I’ll be ok handling Hydrochloric Acid as you suggest –
keep the place well ventilated – don’t breath the fumes - wear old clothing, gauntlets and goggles - children and pets well away. After pouring into the gully and leaving for at least 30mins I’ll wash through with plenty of cold water from the bath.
I’ve seen Hydrochloric acid on sale as Patio cleaner, but I assumed that was fairly dilute. Do you know if I can buy more concentrated HCl at a Builder’s Merchants ?
Cheers
DeckChair-Dave